Jack and tie-down systems for vehicle mounted camper units and cargo units generally include front and/or rear jack units which in transport remain exposed for coaction with a portion of the vehicle for tie-down purposes. Such systems are shown, for example, in U.S. Pat. Nos. 3,532,236, 3,580,599, 3,415,490; 3,698,758 and 4,044,999. The exposed jack units, in vehicle travel, detract from the overall appearance of the vehicle-cargo unit assembly; are subject to being damaged and frequently cause personal injury by being inadvertently walked into or bumped against. The tie-down structure, when exposed, is subject to weather and road conditions and resultant wear and inconvenient manipulation.